On the morning of April 30, 1943, a fisherman working off the coast of Huelva, Spain found a body floating in the water. The corpse, an adult male, was badly decomposed and wearing a military uniform, trench coat, and boots. Floating nearby, and attached to the man’s trench coat belt with a chain, was a briefcase.

The fisherman alerted the authorities and the body was retrieved. The contents of the briefcase, a mix of military documents and personal effects, identified the man as Major William Martin of the Royal Marines. A few days later, Martin’s body was turned over to British forces stationed in Spain and he was given a burial with full military honors. Martin’s briefcase did not accompany him, though, and London sent a slew of frantic messages to their forces in Spain asking for the quick, quiet return of the sensitive documents it contained.

Spain was a non-belligerent in the war, but Franco’s government supported the Axis Powers ideologically and materially, and German agents were able to get the Spanish to give them a peek at the case before it was returned to England. Amid Martin’s various papers—a used bus ticket, a letter from a bank demanding payment of an overdraft fee—they found a letter addressed to a senior British officer in North Africa from the vice-chief of the Imperial General Staff. A letter like that, delivered in a briefcase chained to a officer courier, would no doubt contain useful intelligence.

The German agents slid a thin metal rod through a hole in the side of the envelope, wound the letter around it and then pulled it out without breaking the envelope’s seals. They were right about the letter: It revealed the Allies’ next big move in southern Europe and explained plans for British and American forces in North Africa to cross the Mediterranean and capture Greece and Sardinia. Copies of the letter were sent to Hitler and the German high command, which strengthened its forces in the Mediterranean, and the original was slipped back into the envelope and returned to London.

“Swallowed Whole”

Normally, Allied intelligence falling so easily into Nazi hands would have been called a disaster, but in this case, everything happened exactly as it was supposed to. The letter, the briefcase and the body were actually all part of an elaborate hoax—dubbed Operation Mincemeat—cooked up by British intelligence to mask the Allies’ real plans.

Knowing the Spanish would probably share anything they found with the Germans, two British intelligence officers, Charles Cholmondeley and Ewen Montagu, hit upon the idea of letting them “intercept” false documents under the guard of a courier who’d met an untimely end in a plane crash at sea. If the plan sounds like something out of a paperback thriller, it is. Cholmondeley and Montagu got the idea from a memo written by a naval intelligence officer named Ian Fleming, who’d gotten it from a pre-war detective story called The Milliner’s Hat Mystery (Fleming would also go on to write some novels of his own).

With help from the famed forensic pathologist Bernard Spilsbury, Cholmondeley and Montagu sought out a specific corpse to play their courier. They needed a body that looked like it had spent several days at sea and offered few clues as to the cause of death. There were plenty fitting that description in London’s morgues, but acquiring any of them would be difficult without raising suspicion. If military intelligence asked the next of kin for a body, but couldn’t reveal what they needed it for, people would surely gossip, and who knew how far that talk might travel.

With help from a London coroner, they were able to find a man with no known relations and whose body had gone unclaimed. The man had died from ingesting rat poison, either by accident or with the intent to kill himself. The dose was small enough that it probably took him several painful days to die, but it left few clues as to what had happened to him.

Their body secured, Cholmondeley and Montagu started on the work of building from scratch the man who it had belonged to, filling his life with little details and his pockets and briefcase with odds and ends. Their creation, Major William “Bill” Martin, Royal Marines, was born in 1907 in Cardiff, Wales. He had a fiancee named Pam, and carried a snapshot of her (really an MI5 clerk) in his pocket. Before his death at sea, he’d purchased a diamond engagement ring from a London jeweler, and still had the receipt on him. He also carried a letter from his father, ticket stubs from the theater, a receipt for a dress shirt, a hotel bill, a St. Christopher medallion, and other items.

In the early morning hours of April 30, the submarine HMS Seraph surfaced about a mile off the Spanish coast. The crew fitted “Major Martin” with a life jacket, attached his briefcase to his coat, read Psalm 39 over his body and then set it out to drift at sea. Two weeks later, when Martin’s briefcase was returned to England, British intelligence analyzed the letter he’d been tasked to deliver and figured out that the Germans had slyly opened it. They sent a simple confirmation to Winston Churchill of their success: “Mincemeat Swallowed Whole.”

Over the next several weeks, the Germans redistributed their defensive forces in the Mediterranean. Additional minefields were laid down, panzer divisions were rerouted to Greece, and General Erwin Rommel was sent to oversee operations there. On July 9, Allied forces launched Operation Husky and struck at their true target, an under-defended Sicily.

The Real Major Martin

Mincemeat was a success, and as the story was told and retold and even turned into a movie after the war, one question was on many people’s minds: Who was Major Martin? The picture on Martin’s ID card belonged to MI5 officer Ronnie Reed, that much was known. But who was the poor soul, so hungry or so desperate to die that he’d eaten rat poison, whose body cleared the path to Sicily, and is still buried in Huelva?

There are several candidates. In 1996, a historian named Roger Morgan suggested that Major Martin was really Glyndwr Michael. Originally from Wales, Michael was an alcoholic and was living on the streets of London during the war. On January 26, 1943, he was discovered in an abandoned warehouse and taken to a nearby hospital to treat “acute chemical poisoning” that the doctors attributed to rat poison. He soon died, and his body was kept in the morgue until a family member could be located. In researching a book about Mincemeat more than a decade later, Canadian historian Denis Smyth uncovered additional, previously unseen evidence supporting Morgan’s idea.

In 2003, filmmaker Colin Gibbon released a documentary making the case that Major Martin was really Tom Martin, a Royal Navy sailor who served aboard the HMSDasher. In March 1943, the Dasher suffered an internal explosion and sank, losing 379 crew. In their book The Secrets of HMS Dasher,authors John and Noreen Steele claim that it was actually the body of another sailor from the ship, John Melville, who was used in Mincemeat. In 2004, a memorial service was held on another ship currently in service named the Dasher, where the commanding officer of the ship's naval squadron recognized Melville as Martin in a speech.

Officially, the Royal Navy, Naval Historical Branch, and Ministry of Defense have long recognized Gyndwr Michael as the man whose body was used, and Martin’s gravestone in Spain reads: William Martin, born 29 March 1907, died 24 April 1943, beloved son of John Glyndwyr and the late Antonia Martin of Cardiff, Wales. Glyndwr Michael; Served as Major William Martin, RM.